1. Field of the Invention
This invention relates generally to hip surgeries and, more particularly, relates to surgical methods and tools for preparing a femur and trialing the femur for an implant.
2. Related Art
Most modular systems require instrumentation comprising distal stem trials, proximal sleeve trials, proximal body segment trials, and trial necks to replicate the implant. An implant is then selected based on the trial instrumentation that provides the best fit for the patient. Using distal stem trials adds to the number of instruments in system, therefore increasing inventory overhead and cost of manufacture. More instruments may also lead to confusion in the OR, and a larger cleanup/sterilization operation. There is also a need to simplify instrumentation in such a way that surgical assistants are not burdened by handling large, heavy instrument sets.
With conventional systems, a surgeon must remove distal reamers from the femoral canal and replace them with a distal stem trial connected to a proximal stem trial. Each time a reamer is removed and a distal stem trial is inserted in its place, there are risks of fracture and/or excessive bone removal, because the distal stem trial adds an additional scratch-fit step. In cases of poor bone quality, these risks may be substantially increased. In addition to an increased risk of fracture for each reamer removal step, there is also an increased OR time for the surgeon. The time it takes to ream the femoral canal, remove the reamer from the femoral canal, and implant a distal stem trial can be costly.
The present invention is more advantageous than conventional methods, because the distal reamer serves two purposes instead of one, thereby reducing the number of steps and parts needed to perform the same surgical procedure. The distal reamer is first used to distally ream the femoral canal, and then it is left in place within the canal. The distal reamer is configured to allow a proximal trial and trial neck assembly to be connected to it in such a way that trial reduction may be performed immediately after the distal reamer has stopped cutting. Modular neck segments of the present invention allow quick trial reduction with the reamer still within the femoral canal. By trialing off of the reamer, the present invention avoids a set of separate stem trials.
The standard practice for implanting a hip system is to prepare the bone using a first set of instruments, and then perform a trial reduction using a second set of instruments that is different from the first set. Conventionally, reamers clear a passage within a femoral canal, and then a trial stem is selected from a kit and inserted into said passage. Trial reduction takes place using the trial stem. After the joint is reduced, the trial stem is removed from the femoral canal and then replaced with the correspondingly sized implant stem. This standard practice generally takes more time to perform and is less efficient than the present invention, because more instruments and method steps are needed to carry out the same procedure. More time in the OR means exposing patients to more risk, and increasing hospital overhead. Another practice for implanting a hip system is to prepare the bone using a first set of instruments, and then perform a trial reduction using the same first set of instruments.